Eternalia

“She stood at the edge of a glassy river lined with impossibly tall trees, fanning out their wide emerald leaves among the puffy white clouds. Across the river, a row of crystal castles glittered in the sunlight in a way that would make Walt Disney want to throw rocks at his "Magic Kingdom." To her right, a golden path led into a sprawling city, where the elaborate domed buildings seemed to be built from brick-size jewels--each structure a different color. Snowcapped mountains surrounded the lush valley, and the crisp, cool air smelled like cinnamon and chocolate and sunshine.”

—Narration, in Keeper of the Lost Cities

Eternalia is the capital of the Elvin cities. The human name for Eternalia is Shangri-La, a mythological place

A sketch by Shannon Messenger of a castle in Eternalia

known as 'paradise.' The buildings are tall and built with shining crystals that give them a beautiful sheen. It is a noble city, so people outside the nobility can't be there. In Book Three: Everblaze, the city was practically destroyed by the raging flames. Even so, gnomes and dwarves are rebuilding Eternalia to be bigger and better than ever. Eternalia is also where the Councillors live in their castles In Book 5: Lodestar, Sophie and Fitz go there to get help from Councillor Oralie, who tells them that Councillor Alina took Kenric's castle next to her.